Will normal London travel cards (for underground and overground) work on Crossrail?

When it actually opens, will normal underground and overground tickets work for Crossrail? Or would that be a seperate expensive ticket
Yes, I believe the plan is that the usual TfL fares will apply to journeys within London, and fares for longer journeys (e.g. from places in Buckinghamshire to places in Essex via Crossrail) will be the same as the ones for current routes.
Oyster Cards or Travelcards loaded on to an Oyster Card will work on Crossrail except outside the London zones
The mayor has said - “I intend that such fares will be in line with those charged on LU/DLR, and that the full ticketing range including Oyster Cards, Travelcards, Freedom Passes and Zip cards will be valid on Crossrail services.”
I don't know that anyone has made a formal announcement yet - but it seems reasonable to assume that all of the normal London tickets (including Oyster) will be valid on those parts of the line which are within the TfL area (as for most other rail routes.